Electric kettle, or gas kettle? Which is cheapest? RESULT!

[wmrcomputers]

I (for some reason out of boredom), asked myself this question today.
WHICH IS CHEAPER TO BOIL??

Searching loads of forums people were giving mathematical equations that proved gas to work out more expensive due to the time it takes, plus the efficiency of each method etc.
However, NOBODY had actually got any hard figures to prove it, and some people doubted their reasoning. I decided a true test was the only certain way to know.

So just in case anybody is as curious as I was, here are my findings! I went a weird way of working the gas one out - so if anyone finds a fault in my maths please tell me!



ELECTRIC
My cost 13.61p/kWh
kettle rating 2.8kW
Time to boil 1 litre - 180 seconds
13.61 x 2.8 = cost per hour 38.1p
38.1p/60 = cost per minute = 0.635p
Cost to boil 1 litre = 1.9 pence


GAS
I am told there are about 11kWh's to a cubic metre of gas.
My cost 3p/kWh
3p x 11kWh = 33p per cubic metre
33p / 1000 = 0.033p per thousandth of a cubic metre
Boiled 1 litre of water on gas hob
Opening gas reading = 4603.026
Closing gas reading = 4603.048
difference 0.022
22 (thousandths of a cubic meter) x 0.033p
Cost to boil 1 litre = 0.73 pence

GAS KETTLE GAVE A SAVING OF OVER 61% compared to electric kettle!!

Gas is not as efficient at the point of use, but then electricity is far less efficient over it's journey to you. Therefore any slight difference in CO2 would be negligible. And not only are you saving money but the lack of efficiency at point of use is helping to heat your home too, rather than being "just lost" on it's journey to you.

Time taken to boil on gas was roughly double - but I can happily wait for the whistle!

NOW - This may sound like I wasted an hour of my day, but I then went on to calculate an average saving of nearly £100 a year based on our kettle usage! Also, if you burn out kettles regularly like us that's more money to save.
AND - How many of us re-boil the kettle again because we forgot to make the brew 30 minutes ago?? That whistle would remind you to make it!

Anyone else thinking of switching?????

 

[shoes]

Well done professor whatsgoingon!

Buggered if I can be arsed with a gas kettle, but interesting nonetheless!

 

[Gramaisc]

Seems about right to me.

I attached my integrating watt-hour meter to my electric kettle for a week and found that it cost me around 20p for the full week's use. This was in the summer and I did make a point of boiling just what was required..

 

[Wormella]

Hoorah - we use the gas to heat our kettle - for one we are short of plugs, and now I've gotten into the rhythm of waiting for it to boil, I find I appreciate my tea / coffee more - especially in the case of our coffee which I tend to grind as we need it.

 

[wmrcomputers]

@Gramaisc - Is that a single appliance type of meter?

I just tried putting the sensor of my home electricity monitor around my lightshow supply cable to monitor just what electricity that uses, but my meter is showing nothing when it should be. I think it's to do with the cable diameter not being thick enough to contact the magnets all round, but I'm not sure.

 

[Goldilox]

Hoorah - we use the gas to heat our kettle - for one we are short of plugs, and now I've gotten into the rhythm of waiting for it to boil, I find I appreciate my tea / coffee more - especially in the case of our coffee which I tend to grind as we need it.

I pushed for it because to me it seemed logically true that using natural gas to boil water in a power station, and then using the steam to generate electricity, then using that electricity to boil water in my home was going to be less efficient than piping that gas to my home and boiling the water there. Even if a power station can heat their water more efficiently than I can, there's still an extra two processes for energy losses to take place.

Glad you've proved me correct!

 

[wmrcomputers]

You've hit the nail on the head there Goldilox.

A lot of forum users (elsewhere) argue that a kettle is 100% efficient as the element is inside the water and there is therefore no waste at all.... but they forget things like you have just mentioned. Looking further into it, some experts say that electricity is only around 35% efficient from the energy used to produce it, to what actually reaches our homes. I find that very believeable, but also shocking!

Now, if only we could have our own back yard generator running on natural gas, I reckon we'd be quids in!

 

[wmrcomputers]

... and the 35% efficiency mentioned above gives you the answer to "why is electricity 4x more expensive than gas?". Answer, because we actually have to pay for what we can't have!

 

[Rikki]

Now, if only we could have our own back yard generator running on natural gas, I reckon we'd be quids in!

You can (or soon will be able to) search for combined heat and power boilers.

 

[wmrcomputers]

hmmm. interesting stuff.

 

[Gramaisc]

@Gramaisc - Is that a single appliance type of meter?

I just tried putting the sensor of my home electricity monitor around my lightshow supply cable to monitor just what electricity that uses, but my meter is showing nothing when it should be. I think it's to do with the cable diameter not being thick enough to contact the magnets all round, but I'm not sure.

Yes, one of the plug through ones, very handy. £7 from Lidl, every now and then.

You need to put the sensor of a 'whole house meter' around either the live or neutral wire, both not both, or the fields will just cancel each other out. If you have it around a two or three core cable then it should read zero, if all is well..

 

[henryscat]

Mustard mit I prefer gas kettles, but sadly don't have a gas stove any more

There is some debate around how efficiently the heat from the gas hob gets transferred to the water with losses around the side of the kettle and heating the kettle itself. That said, environmentally it has to be better on a gas hob because you haven't got the whopping inefficiency of Rugeley Power Station to contend with.

At the moment I've got a leccy kettle with variable thermostat, so can just heat the water up to 80 degrees rather than boiling for a drink.

There's also these sorts of efforts that are sposed to use less because they only heat the amount needed:
http://www.argos.co.uk/static/Product/partNumber/4230429.htm

 

[Gramaisc]

I'm still waiting for a Kelly Kettle to turn up at the boot sale. It offers a, probably, more efficient heat transfer arrangement than a standard domestic kettle...

Gas kettles like this -

are still available, with a spiral heat exchanger in a raised base, but whether it really does improve the heat transfer efficiency much, I'm not sure..

 

[wmrcomputers]

Argos used to sell them heat exchanger one's (rapid boil), but can't seem to find one on their website - as it is what I would have preffered to purchase.
Instead looks like a standard one it will have to be. (budget a bit tight now anyway)

 

[Gramaisc]

They're not cheap, but are sometimes to be found in charity shops - try the Co-op if you are desperate for one.

The ones with the dimple in the spout, as seen above, do whistle as well. The whistle is in the lid and the dimple retains the ball-valve that makes it work..

 

[Gramaisc]

£21 and 40 minutes left.

 

[tek-monkey]

Is it better to boil cold water, or hot water from your tap? Surely the boiler is more efficient than the kettle?

Those heat/power boilers look interesting.

 

[Gramaisc]

Drinking water from a hot water system is not really advisable, especially one with a storage tank. There can be issues over leaching of metals into the water and the possibilties of unwanted bacterial growth are raised. Just heat water direct from the cold tap, in the quantities that you require, when you require it, that's my advice.

 

[wmrcomputers]

£21 and 40 minutes left.

Blimey - I can't believe how much it's fetching considering how "used" it looks (7 years it says)

How expensive were these new then??

 

[wmrcomputers]

@Tek - what Gramaisc says. You don't wanna go drinking that stuff